Maretron SSC200 User Manual

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SSC200  
Solid State Rate/Gyro Compass  
User’s Manual  
Revision 1.8  
Copyright © 2012 Maretron, LLP All Rights Reserved  
Maretron, LLP  
9014 N. 23rd Ave #10  
Phoenix, AZ 85021-7850  
Maretron Manual Part #: M000401  
Revision 1.8  
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Table of Contents  
2.4.1 Connecting to NMEA 2000® Interface ........................................................6  
If the NMEA 2000® interface is connected, power is supplied to the SSC200  
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Table of Figures  
Figure 3 – NMEA 2000® / NMEA 0183 Interface Connector Locations ..................................... 6  
Figure 4 – NMEA 2000®/Power Connector Face Views ............................................................ 6  
Figure 5 - SSC200 with NMEA 2000® Connection Only ............................................................ 7  
Table of Appendices  
Appendix A – NMEA 0183 Interfacing ..................................................................................... A1  
Appendix B – NMEA 2000® Interfacing.................................................................................... B1  
Appendix C – Connecting to a PC Via NMEA 0183.................................................................C1  
Appendix D – Configuring the SSC200 to Transmit True Heading Data .................................D1  
Appendix E – Configuring the SSC200 to Transmit the HDT Sentence for …and Radars ...... E1  
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1 General  
1.1 Introduction  
Congratulations on your purchase of the Maretron SSC200 Solid State Rate/Gyro Compass.  
Maretron has designed and built your compass to the highest standards for years of reliable,  
dependable, and accurate service.  
The SSC200 detects the direction of the earth’s magnetic field using solid state  
magnetometers and indicates the vessel heading relative to magnetic north. In addition, the  
SSC200 incorporates solid state accelerometers and a solid state angular rate sensor for  
indicating the vessel’s attitude (pitch and roll) and rate of turn.  
The Maretron SSC200 is designed to operate within the harsh demands of the marine  
environment. However, no piece of marine electronic equipment can function properly unless  
installed, calibrated, and maintained in the correct manner. Please read carefully and follow  
these instructions for installation, calibration, and usage of the Maretron SSC200 in order to  
ensure optimal performance.  
1.2 Firmware Revision  
This manual corresponds to SSC200 firmware revision 2.0.  
1.3 Features  
The Maretron SSC200 Solid State Compass has the following features.  
NMEA 2000® and NMEA 0183 Interfaces  
Solid State Magnetometers for Indicating the Vessel’s Heading  
Solid State Accelerometers for Indicating the Vessel’s Attitude (Pitch and Roll)  
Solid State Angular Rate Sensor for Indicating the Vessel’s Rate of Turn  
Advanced Kalman Filtering for Stable and Accurate Output During Dynamic Conditions  
Fast Response Time Stabilizes Auto-Pilot Systems  
Calibration for Compensating Magnetic Deviation Caused by Hard and Soft Iron Effects  
Installation-Offset Capability for Aligning the Compass to the Vessel  
Programmable Variation  
Waterproof Enclosure and Cable System  
1.4 Quick Install  
Installing the Maretron SSC200 compass involves the following six steps. Please refer to the  
individual sections for additional details.  
1. Unpack the Box (Section 2.1)  
2. Choose a Mounting Location (Section 2.2)  
3. Mount the SSC200 Compass (Section 2.3)  
4. Connect the SSC200 Compass (Section 2.4)  
5. Calibrate the SSC200 Compass for Magnetic Deviation (Section 3.1)  
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6. Calibrate the SSC200 Compass for Installation-Offset (Section 3.2)  
7. Use Default Variation Source or Select an Appropriate Variation Source (Section 4)  
2 Installation  
2.1 Unpacking the Box  
When unpacking the box containing the Maretron SSC200, you should find the following items.  
1 - SSC200 Solid State Compass  
2 - Mounting Brackets  
4 - Mounting Bracket Screws  
4 - Mounting Screws  
1 - 10 meter NMEA 0183 Cable*  
1 - NMEA 2000® Micro Field Attachable Connector (Female)*  
1 - SSC200 User’s Manual  
1 - Warranty Registration Card  
* Only included in SSC200-01  
If any of these items are missing or damaged, please contact Maretron.  
2.2 Choosing a Mounting Location  
The selection of a suitable mounting location is important for the optimal performance of the  
Maretron SSC200. The mounting location and orientation of the Maretron SSC200 should be:  
1. Level with the Earth’s Horizontal Plane – Although the SSC200 can be calibrated in the  
vessel to compensate for pitch and roll installation-offset, it is best to mount the compass as  
level as possible to maximize its pitch and roll operational range.  
2. Oriented with Arrow Pointing to Bow Parallel to Vessel Centerline – Although the SSC200  
can be calibrated in the vessel to compensate for heading installation-offset, it is best to  
mount the compass pointed towards the bow and parallel to the vessel centerline. The  
SSC200 can be mounted in other orientations, although this requires additional  
configuration steps; please refer to Section 2.3 on page 3 for details.  
3. Near the Center of Gravity (CG) of the Vessel – The compass experiences the least amount  
of movement when located at the CG, which allows the most accurate readings. This is  
similar to a traditional card/needle compass, where the farther the compass is from the CG,  
then the more the fluid sloshes around, making accurate readings more difficult.  
4. Away from Structures Containing Ferrous Metals – The earth’s lines of magnetic flux tend to  
become distorted in the vicinity of ferrous metals, which can potentially cause errors in the  
compass’s indicated heading. The SSC200 can be calibrated to compensate for these  
errors, but it is still best to minimize the errors by placing the compass as far away from  
ferrous metals as is practical.  
5. Away from Magnetic Field Sources – Power or ignition cables, electric motors, and other  
electronic equipment can create magnetic fields. The earth’s lines of magnetic flux tend to  
become distorted in the vicinity of magnetic field sources, which can potentially cause errors  
in the compass’s indicated heading. The magnetic fields tend to come and go as power is  
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switched on and off, which makes compensation impractical. Therefore, you should try to  
mount the compass as far away as possible from these magnetic field sources (doubling the  
distance between the magnetic field source and the compass will reduce the field strength  
by a factor of approximately 8). Also, always observe any “compass-safe distance” markings  
on other electronic equipment.  
6. Minimal Vibration – Although the SSC200 is more tolerant of vibration than a fluxgate  
compass, it is best to mount the compass in a location free of vibration as opposed to a  
location with vibration.  
2.3 Mounting the SSC200  
The Maretron SSC200 compass can be mounted to a horizontal surface such as a floor or  
deck (Section 2.3.1) or it can be mounted to a vertical surface such as a wall or bulkhead  
(Section 2.3.2).  
2.3.1 Mounting the SSC200 to a Horizontal Surface  
Mounting the SSC200 compass to a horizontal surface requires that the provided mounting  
brackets be fastened to the bottom of the SSC200 using the provided brass flat head screws.  
Once the mounting brackets are securely fastened to the bottom of the SSC200, attach the  
SSC200 securely to the vessel using the included brass mounting screws or other non-ferrous  
fasteners as shown in Figure 1. Do not use threadlocking compounds containing methacrylate  
ester, such as Loctite Red (271), as they will cause stress cracking of the plastic enclosure.  
The usual way of mounting the SSC200 to a horizontal surface is to mount it to the top of the  
horizontal surface; however, the SSC200 may be mounted upside down to the underside of a  
horizontal surface, provided that the SSC200 is programmed to recognized that it is mounted  
upside down. This can be done using a Maretron display product (e.g., DSM200 - please refer  
to the DSM200 user’s manual for details).  
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Figure 1 – Mounting the SSC200 to a Horizontal Surface  
2.3.2 Mounting the SSC200 to a Vertical Surface  
Mounting the SSC200 compass to a vertical surface requires that the provided mounting  
brackets be fastened to the side of the SSC200 using the provided brass flat head screws.  
Once the mounting brackets are securely fastened to the side of the SSC200, attach the  
SSC200 securely to the vessel using the included brass mounting screws or other non-ferrous  
fasteners as shown in Figure 2. Do not use threadlocking compounds containing methacrylate  
ester, such as Loctite Red (271), as they will cause stress cracking of the plastic enclosure.  
The usual way of mounting the SSC200 to a vertical surface is attaching the SSC200 to the  
forward side of a vertical surface, so that the side of the compass with the connectors is facing  
the bow of the boat; however, the SSC200 may be mounted to the astern side of a vertical  
surface, so that the side of the compass with the connectors is facing the stern of the boat,  
provided that the SSC200 is programmed to recognized that it is mounted in this way  
(“backwards”). This can be done using a Maretron display product (e.g., DSM200 - please  
refer to the DSM200 user’s manual for details).  
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Figure 2 – Mounting the SSC200 to Vertical Surface  
2.4 Connecting the SSC200  
You have a choice of connecting the SSC200 to a NMEA 2000® interface (Section 2.4.1),  
NMEA 0183 interface (Section 2.4.2), or connecting both interfaces simultaneously (Section  
2.4.2.2).  
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NMEA 2000 / Power  
Connector  
NMEA 0183 Connector  
Figure 3 – NMEA 2000® / NMEA 0183 Interface Connector Locations  
2.4.1 Connecting to NMEA 2000® Interface  
The Maretron SSC200 provides a connection to an NMEA 2000® interface through a five pin  
male connector (Figure 4). You connect the SSC200 to an NMEA 2000® network using a  
Maretron NMEA 2000® cable (or compatible cable) by connecting the female end of the cable  
to the SSC200 (note the key on the male connector and keyway on the female connector) as  
shown in Figure 5 below.. Be sure the cable is connected securely and that the collar on the  
cable connector is tightened firmly. Connect the other end of the cable (male) to the NMEA  
2000® network in the same manner. The SSC200 is designed such that you can plug or unplug  
it from an NMEA 2000® network while the power to the network is connected or disconnected.  
Please follow recommended practices for installing NMEA 2000® network products.  
Figure 4 – NMEA 2000®/Power Connector Face Views  
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Figure 5 - SSC200 with NMEA 2000® Connection Only  
2.4.2 Connecting to NMEA 0183 Interface  
The Maretron SSC200 provides a connection to an NMEA 0183 interface through an eight pin  
male connector (Figure 6). You connect the SSC200 to an NMEA 0183 network using the  
Maretron supplied 10 meter cable by connecting the female end of the cable to the SSC200  
(note the key on the male connector and keyway on the female connector). Be sure the cable  
is connected securely and that the collar on the cable connector is tightened firmly.  
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Figure 6 – NMEA 0183 Connector Face Views  
Connect the other end of the cable consisting of individual wires using recommended practices  
for installing NMEA 0183 products. Please note that NMEA 0183 does not have a standard for  
connectors and the customer/installer should contact the manufacturer of the equipment to  
which the SSC200 is being connected for information on how to properly connect the device to  
the SSC200. The individual wires found within the cable have the following color coding.  
Wire Color  
Gray  
Name  
TXA  
TXB  
RXA  
RXB  
Description  
Transmit Differential Output A Signal  
Transmit Differential Output B Signal  
Receive Differential Input A Signal  
Receive Differential Input B Signal  
Brown  
Blue  
White  
Figure 7 – NMEA 0183 Cable/Wire Color Coding  
2.4.2.1Power Connections  
If the NMEA 2000® interface is connected, power is supplied to the SSC200 through the NMEA  
2000® network connection.  
If only the NMEA 0183 interface is used, power connections must be made via the NMEA  
2000®/Power connector. Using the included Micro Field Attachable Connector (Female),  
connect two power wires (not included) to pins 2 and 3 of the field attachable connector (only  
the two power pins need be connected) as shown in Figure 4 on page 6, assemble the  
connector per the instructions packaged with the connector, and screw the connector snugly  
into the NMEA 2000®/Power connector on the SSC200, as shown in Figure 8 below.  
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Figure 8 - SSC200 with NMEA 0183 Connection Only  
2.4.2.2Supported NMEA 0183 Baud Rates  
The SSC200 compass supports NMEA0183 communication at both 4800 baud and 38400  
baud. All SSC200 Compasses are shipped with a baud rate of 4800 baud. The baud rate may  
be set to 38400 baud by connecting to the compass using a teminal emulator (See Appendix C  
for details) and sending the following strings to the compass through the NMEA 0183  
connection:  
shell  
This will cause the “cmd>” command prompt to be displayed  
tm setbaud 38400  
At this point, you must change the baud rate of your connection to 38400 baud to continue, as  
the SSC200 has now been set to the higher baud rate.  
tm storebaud  
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This causes the new baud rate to be stored to non-volatile memory, so the compass will retain  
this baud rate when it is powered down.  
2.4.3 Connecting Both NMEA 2000® and NMEA 0183 Interfaces  
The SSC200 can be simultaneously connected to both an NMEA 2000® network and an NMEA  
0183 network.  
2.4.4 Checking Connections  
Once the NMEA 2000®/Power and/or NMEA 0183 connections to the Maretron SSC200 have  
been completed, check to see that heading information is being properly transmitted by  
observing an appropriate display. Refer to Section 7, “Troubleshooting”, if no heading  
information appears, otherwise proceed to Section 3 entitled “Calibration”.  
3 Calibration  
In order to provide accurate heading indication, the SSC200 must be calibrated in the vessel  
after installation. The two calibration procedures that must be carried out are magnetic  
deviation calibration (Section 3.1) and installation-offset correction (Section 3.2).  
These procedures should be carried out after the initial compass installation and again at any  
time that the magnetic environment of the vessel has changed significantly (for example, new  
cables have been routed near the compass or new equipment made of ferrous metal has been  
installed near the compass).  
WARNING: It is imperative that calibration procedures be carried out upon installation  
of the SSC200 to ensure accurate readings.  
3.1 Magnetic Deviation Calibration  
Magnetic and/or ferrous items near a magnetic compass such as the SSC200 can cause  
errors in the compass’ heading output. These errors are referred to as magnetic deviation.  
The Maretron SSC200 compass can compensate for heading errors caused by magnetic  
deviation by learning about the magnetic environment in which it has been mounted. This is  
done using one of four possible magnetic deviation calibration procedures.  
1. Maretron Display Product Initiated (Section 3.1.1)  
2. Automatically at Power-Up (Section 3.1.2)  
3. Through the NMEA 0183 Interface (Appendix A)  
4. Through the NMEA 2000® Interface (Appendix B)  
All the procedures require that the vessel be turned in successive circles during which time the  
SSC200 uses changing heading information along with readings from the angular rate sensor  
to calculate hard and soft iron magnetic deviation. Upon a successful completion of deviation  
calibration, the SSC200 stores the deviation values in permanent memory for subsequent  
compensation. Under certain conditions (e.g., turning to fast or to slow), the SSC200 will not  
successfully complete the calibration process and the SSC200 will not store the deviation  
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values in its permanent memory. Therefore, it is important to verify that the deviation  
calibration process completed successfully.  
The preferred method for deviation calibration is to use a Maretron display (procedure 1)  
because you receive direct feedback on the calibration process with a clear indication of a  
successful or unsuccessful deviation calibration. Deviation calibration done automatically at  
power-up (procedure 2) is less desirable than procedure 1 because it is more difficult to verify  
that a successful deviation calibration completed. As an alternative to procedures 1 and 2,  
users with direct access to the NMEA 0183 and NMEA 2000® interfaces can perform magnetic  
deviation calibration directly through the NMEA 0183 interface (see Appendix A) or the NMEA  
2000® interface (see Appendix B). These direct access methods also provide an indication of a  
successful deviation calibration or an indication of an unsuccessful deviation calibration and  
the corresponding reason for the failure.  
3.1.1 Maretron Display Initiated Deviation Calibration  
Maretron display initiated deviation calibration is accomplished by turning the vessel through  
successive circles while the SSC200 receives a command from a Maretron display product  
(e.g., DSM200). The procedure is as follows:  
1. Ensure that the compass has been properly installed per Section 2.  
2. Warm up the compass by operating it for approximately 10 minutes.  
3. Turn the vessel (either direction) such that you complete a full 360° turn in 2½ minutes  
or less (try not to go below 1 minute for a complete circle).  
4. While continuing to turn the vessel as indicated in step 3, use the display’s menu items  
to locate and send the deviation calibration command (please refer to the display  
product user’s manual).  
5. Continue turning the vessel through at least three complete circles until the display  
indicates a successful deviation calibration.  
While turning the vessel, try to maintain a circle by holding the rudder at a constant angle. In  
addition, try to minimize the vessel’s pitch and roll by calibrating on calm, flat water.  
After deviation calibration is complete, the results of the deviation calibration, which indicate  
the quality of the compass installation environment, may be seen using a Maretron display  
product (e.g., DSM200 - please refer to the DSM200 user’s manual for details). This allows  
you to compare different installation points on a vessel to determine the optimum location for  
the SSC200.  
3.1.2 Automatic Power-Up Deviation Calibration  
Automatic power-up deviation calibration is accomplished by turning the vessel through four  
complete circles within 10 minutes of power-up. The procedure is as follows:  
1. Ensure that the compass has been properly installed per Section 2.  
2. Warm up the compass by operating it for approximately 10 minutes.  
3. Turn the vessel (either direction) such that you complete a full 360° turn in 2½ minutes  
or less (try not to go below 1 minute for a complete circle).  
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4. While continuing to turn the vessel as indicated in step 3, remove the power from the  
compass and reapply power (this initiates deviation calibration).  
5. Continue turning the vessel through four complete circles in less than 10 minutes from  
the time power was applied.  
6. Successful deviation is indicated when the SSC200 outputs the following sequence:  
a) 0 Degrees for two seconds followed by  
b) 90 degrees for two seconds followed by  
c) 180 degrees for two seconds followed by  
d) 270 degrees for two seconds followed by the actual heading  
While turning the vessel, try to maintain a circle by holding the rudder at a constant angle. In  
addition, try to minimize the vessel’s pitch and roll by calibrating on calm, flat water.  
3.2 Installation-Offset Correction  
After installation and successful deviation calibration, it is important to perform installation-  
offset correction so that the displayed compass heading, pitch, and roll match the actual vessel  
heading, pitch, and roll. Installation-offset correction is done using one of four possible  
procedures.  
1. Maretron Display Product Initiated (Section 3.2.1)  
2. Manual Installation-Offset Correction (Section 3.2.2)  
3. Through the NMEA 0183 Interface (Appendix A)  
4. Through the NMEA 2000® Interface (Appendix B)  
The preferred method for installation-offset is to use a Maretron display (procedure 1) which  
will automatically calibrate the SSC200 without physically adjusting the compass as describe  
under procedure 2 (Manual Installation-Offset Correction). As an alternative to procedures 1  
and 2, users with direct access to the NMEA 0183 and NMEA 2000® interfaces can perform  
installation-offset correction through the NMEA 0183 interface (see Appendix A) or the NMEA  
2000® interface (see Appendix B).  
3.2.1 Maretron Display Product Offset Correction  
Installation-offset correction can be performed using a Maretron display product (e.g.,  
DSM200). The procedure is as follows:  
1. Make sure the vessel is laying in flat water on a known heading.  
2. Use the display’s menu items to locate and send the compass installation-offset  
correction command (please refer to display product user’s manual).  
3.2.2 Manual Installation-Offset Correction  
Manual installation-offset correction is performed by physically aligning the compass with the  
vessel. The procedure is as follows:  
1. With the vessel laying flat in the water, adjust the roll angle of the SSC200 by adding  
small washers or spacers between the mounting bracket holes and mounting surface  
until the display reads zero for the roll angle (skip this step if you are not interested in  
viewing the vessel’s roll angle).  
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2. With the vessel laying flat in the water, adjust the pitch angle of the SSC200 by adding  
small washers or spacers between the mounting bracket holes and mounting surface  
until the display reads zero for the pitch angle (skip this step if you are not interested in  
viewing the vessel’s pitch angle).  
3. With the vessel laying flat in the water on a known heading, adjust the heading of the  
SSC200 by rotating it until the display reads the known vessel heading.  
4. Recheck that the roll and pitch readings are zero and that the indicated heading is  
correct (repeat steps 1 through 3 as necessary).  
5. Securely fasten the SSC200 by tightening the mounting screws.  
4 Variation  
Variation is the angular difference between the true meridian (great circle connecting the  
geographic poles) and the magnetic meridian (direction of the lines of magnetic flux). Variation  
has different values at different locations on the earth with most areas undergoing change to  
the variation over time.  
Normally, heading information is displayed as either a “true” heading (a direction relative to the  
geographic poles) or it is displayed as a “magnetic” heading (a direction relative to the lines of  
magnetic flux). North-seeking gyrocompasses are capable of measuring direction relative to  
the geographic poles (“true”) whereas magnetic compasses measure direction relative to the  
earth’s local magnetic flux (“magnetic”).  
The SSC200 is a magnetic compass; therefore, it requires an external source for variation if  
you want to view your heading in “true” format. The SSC200 is capable of receiving variation in  
one of three ways; 1) via the NMEA 0183 interface, 2) via the NMEA 2000® interface, or 3)  
through manual variation entry.  
Normally, the SSC200 will automatically use variation from either the NMEA 0183 interface or  
the NMEA 2000® interface, however, you can force the SSC200 to use variation from only the  
NMEA 0183 interface or you can force the SSC200 to use variation from only the NMEA 2000®  
interface or you can force SSC200 to only use manually entered variation.  
WARNING: Multiple variation sources that are received by the SSC2000 (i.e., NMEA 0183  
and NMEA 2000® interfaces) will cause confusion as to the correct source to be used for  
true heading indications. If more than one variation source is available, then the SSC200  
needs to be programmed to use the appropriate source for reporting subsequent true  
heading information. See Section 4.4 for details on choosing a specific variation source  
when more than one variation source is available.  
4.1 Variation Input via NMEA 0183 Interface  
As shipped from the factory, the SSC200 automatically looks for variation data coming from  
the NMEA 0183 interface. The SSC200 accepts variation data from the Recommended  
Minimum Specific GNSS Data (RMC) sentence or the SSC200 computes variation from the  
Course Over Ground and Ground Speed (VTG) sentence. If the SSC200 does indeed receive  
variation information from the NMEA 0183 interface, then it will do the following:  
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1. Transmit the Heading, Deviation & Variation (HDG) sentence including the variation  
field as seen from the RMC or VTG sentence over the NMEA 0183 interface if HDG is  
enabled (see Appendix A for enabling or disabling NMEA 0183 sentences).  
2. Transmit the Heading True (HDT) sentence using variation data from the RMC or VTG  
sentence over the NMEA 0183 interface if HDT is enabled (see Appendix A for enabling  
or disabling NMEA 0183 sentences).  
3. Transmit over the NMEA 2000® interface the Magnetic Variation PGN (127258) with the  
Variation Source field value corresponding to the received NMEA 0183 variation data  
from the RMC or VTG sentence. The PGN’s Variation Source field will be transmitted  
with the lowest possible quality indicator, which is “Manual Entry”.  
4.2 Variation Input via the NMEA 2000® Interface  
As shipped from the factory, the SSC200 automatically looks for variation data coming from  
the NMEA 2000® interface. The SSC200 accepts variation data from the Magnetic Variation  
PGN (127258). If the SSC200 does indeed receive variation information from the NMEA 2000®  
interface, then it will do the following:  
1. Transmit the Heading, Deviation & Variation (HDG) sentence including the variation  
field as seen from the Magnetic Variation PGN (127258) from the NMEA 2000 interface  
if HDG is enabled (see Appendix A for enabling or disabling NMEA 0183 sentences).  
2. Transmit the Heading True (HDT) sentence using variation data from the Magnetic  
Variation PGN (127258) from the NMEA 2000 interface if HDT is enabled (see  
Appendix A for enabling or disabling NMEA 0183 sentences).  
4.3 Variation Input via Manual Entry  
If no other source of variation is available (i.e., from either the NMEA 0183 or NMEA 2000®  
interface), the SSC200 can be programmed with a fixed variation value for a given location  
(this value can be found on most navigational charts). If variation is manually entered into the  
SSC200, then it will do the following:  
1. Transmit the Heading, Deviation & Variation (HDG) sentence including the variation  
field as manually entered over the NMEA 0183 interface if HDG is enabled (see  
Appendix A for enabling or disabling NMEA 0183 sentences).  
2. Transmit the Heading True (HDT) sentence using variation data as manually entered  
over the NMEA 0183 interface if HDT is enabled (see Appendix A for enabling or  
disabling NMEA 0183 sentences).  
3. Transmit over the NMEA 2000® interface the Magnetic Variation PGN (127258) with the  
Variation Source field value corresponding to the manually entered variation. The  
PGN’s Variation Source field will be transmitted with the lowest possible quality  
indicator, which is “Manual Entry”.  
WARNING: Magnetic variation changes as your position on the earth changes;  
therefore, the variation should be adjusted with changes in position. The SSC200 will  
not automatically adjust variation with changes in position; it is the responsibility of the  
user to adjust variation with changes in position.  
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4.4 Variation Source Selection  
As shipped from the factory, the SSC200 automatically looks for variation from both the NMEA  
0183 and NMEA 2000® interfaces. If there is only a single source of variation available (either  
from the NMEA 0183 or the NMEA 2000® interface), then there is no need to manually select a  
variation source. However, if there are multiple variation sources (i.e., variation available from  
both the NMEA 0183 and NMEA 2000® interfaces) or there is no source for variation (i.e.,  
variation is not available from either the NMEA 0183 or the NMEA 2000® interfaces), then it is  
necessary to select a particular variation source. The SSC200 can be programmed to  
specifically use one of three possible variation sources:  
1. Variation from Only NMEA 0183 Interface  
2. Variation from Only NMEA 2000® Interface  
3. Variation from Only Manual Entry  
The SSC200 can be programmed to accept a specific source for the variation data using one  
of two possible procedures.  
1. Using a Maretron Display (Section 4.4.1)  
2. Through the NMEA 0183 Interface (Section 4.4.2)  
4.4.1 Variation Source Selection via Maretron Display  
You can program the SSC200 to use a particular variation source using a Maretron display  
product (e.g., DSM200). Refer to the display product user’s manual for details on programming  
the SSC200 to use a specific variation source.  
4.4.2 Variation Source Selection via NMEA 0183 Interface  
You can program the SSC200 to use a particular variation source through the NMEA 0183  
interface. Refer to Appendix A for details on programming the SSC200 to use a specific  
variation source.  
5 Rate of Turn  
The SSC200 is capable of measuring a vessel’s rate of turn and outputting the information  
over both the NMEA 0183 and NMEA 2000® interfaces. Furthermore, the SSC200 has a  
programmable damping period where the filter time can be increased for very slow turning  
vessels such as tugs pushing barges. Also, the SSC200 rate of turn indication may be zeroed  
to correct for any temperature-induced offset.  
The SSC200 can be programmed with different damping periods and have the rate of turn  
indication zeroed using one of two possible procedures.  
1. Using a Maretron Display (Section 5.1)  
2. Through the NMEA 0183 Interface (Section 5.2)  
Revision 1.8  
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SSC200 User’s Manual  
5.1 Rate of Turn Damping Period Selection with Maretron Display  
You can program the SSC200 to use a particular rate of turn damping period using a Maretron  
display product (e.g., DSM200). Refer to the display product user’s manual for details on  
programming the SSC200 to use a specific damping period.  
5.2 Rate of Turn Damping Period Selection by NMEA 0183  
Interface  
You can program the SSC200 to use a particular rate of turn damping period through the  
NMEA 0183 interface. Refer to Appendix A for details on programming the SSC200 to use a  
specific damping period.  
5.3 Rate of Turn Zeroing  
The SSC200 may be used as a rate of turn indicator, which should read zero when the vessel  
is not turning. It is possible that the rate of turn indication has an offset; that is, it may show a  
non-zero value when the vessel is at rest. This offset changes with temperature but the  
SSC200 has the ability to remember the offset at different temperatures. You teach the  
SSC200 by using “Rate of Turn Zeroing”. It is possible to do “Rate of Turn Zeroing” using a  
Maretron display product, such as the DSM200 (please refer to the display product user’s  
manual for details).  
6 Maintenance  
Regular maintenance is important to ensure continued proper operation of the Maretron  
SSC200. Perform the following tasks periodically:  
Clean the unit with a soft cloth. Do not use chemical cleaners as they may remove  
markings or may corrode the compass enclosure or seals. Do not use any cleaners  
containing acetone, as they will deteriorate the plastic enclosure.  
Ensure that the unit is mounted securely and cannot be moved relative to the mounting  
surface. If the unit is loose, tighten the mounting screws and repeat the magnetic  
deviation calibration and installation-offset correction.  
Check the security of the cables connected to the NMEA 2000® and/or NMEA 0183  
interfaces and tighten if necessary.  
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Revision 1.8  
     
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7 Troubleshooting  
If you notice unexpected operation of the Maretron SSC200, follow the troubleshooting  
procedures in this section to remedy simple problems.  
Symptom  
No heading output  
Troubleshooting Procedure  
Check the connections to the NMEA 2000®/Power  
connector and/or NMEA 0183 Connector and tighten if  
necessary  
Ensure that power is supplied to the connected NMEA  
2000® or NMEA 0183 cable  
For NMEA 0183 connections, ensure that the SSC200  
is programmed to transmit the appropriate type of  
sentence (HDT, HDG, or HDM) required by the  
connected equipment.  
If the HDT sentence is being transmitted, ensure that  
the SSC200 is provided with a source of magnetic  
variation information so that it can calculate true  
heading from the magnetic heading.  
Inaccurate heading output Ensure the SSC200 is still mounted securely  
Ensure the SSC200 is still in a clean magnetic  
environment and that no power or ignition cables or  
magnetic or ferrous objects have been moved near the  
SSC200  
Repeat the magnetic deviation compensation and  
installation-offset correction procedures  
Figure 9 – Trouble Shooting Guide  
If these steps do not solve your problem, please contact Maretron Technical Support (refer to  
Section 9 for contact information).  
Warning: There are no user-serviceable components inside the Maretron SSC200.  
Opening the SSC200 will expose the sensitive electronic components to movement and  
adverse environmental conditions that may render the compass inoperative. Please do  
not open the SSC200, as this will automatically void the warranty. If service is required,  
please return the unit to an authorized Maretron service location.  
Revision 1.8  
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SSC200 User’s Manual  
8 Technical Specifications  
Specifications  
Parameter  
Static Heading Accuracy  
Heading Display Resolution  
Settling Time  
Value  
<1° rms  
0.1°  
1 Second  
Comment  
±45° Pitch and Roll - 15°C to 35°C  
With Maretron Display  
To Static Accuracy after 35°/Second Turn  
Automatic or Initiated through Interfaces  
Manual or Initiated through Interfaces  
Heading Deviation  
Alignment Calibration  
Pitch and Roll Range  
Yes  
Yes  
±80°  
Pitch and Roll Accuracy  
Pitch and Roll Display Resolution  
Pitch and Roll to Boat Alignment  
Rate of Turn Range  
<1°  
0.1°  
Yes  
±45° Pitch and Roll - 15°C to 35°C  
With Maretron Display  
Manual or Initiated through Interfaces  
0° - 90° per Second  
±1° per Second  
Rate of Turn Accuracy  
0° Pitch and Roll - 15°C to 35°C  
Certifications  
Parameter  
Comment  
NMEA 2000  
Level A  
Maritime Navigation and Radiocommunication Equipment & Systems  
FCC and CE Mark  
Tested to IEC 60945  
Electromagnetic Compatibility  
NMEA 2000® Parameter Group Numbers (PGNs) - See Appendix B for Details  
Description  
PGN #  
PGN Name  
Default Rate  
Periodic Data PGNs  
127250 Vessel Heading  
127257 Attitude  
127251 Rate of Turn  
10 Times/Second  
1 Time/Second  
10 Times/Second  
Response to Requested PGNs  
Protocol PGNs  
126464 PGN List (Transmit and Receive)  
126996 Product Information  
126998 Configuration Information  
059392 ISO Acknowledge  
059904 ISO Request  
060416 ISO Transport Protocol, Connection  
Management  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
060160 ISO Transport Protocol, Data Transfer  
060928 ISO Address Claim  
065240 ISO Address Command  
126206 NMEA  
N/A  
N/A  
N/A  
N/A  
NMEA 0183 Sentences - See Appendix A for Details  
Description Acronym  
Sentence Name  
Heading, Deviation, and Variation  
Default Rate  
10 Times/Second  
Transmitted HDG  
Sentences  
HDM  
HDT  
ROT  
Heading, Magnetic (Not normally transmitted, see Appendix A)  
Heading True (Not normally transmitted, see Appendix A)  
Rate of Turn  
N/A  
N/A  
5 Times/Second  
1 Time/Second  
N/A  
PMAROUT Maretron Proprietary Attitude (Pitch and Roll)  
TXT  
RMC  
VTG  
Text Transmission  
Recommended Minimum Specific GNSS Data  
Course Over Ground and Ground Speed  
Received  
Sentences  
N/A  
N/A  
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®
Electrical  
Parameter  
Value  
9 to 16 Volts  
<150mA  
3
Comment  
Operating Voltage  
Power Consumption  
Load Equivalence Number (LEN)  
Reverse Battery Protection  
Load Dump Protection  
DC Voltage  
Average Current Drain  
NMEA 2000® Spec. (1LEN = 50 mA)  
Indefinetely  
Yes  
Yes  
Energy Rated per SAE J1113  
Mechanical  
Parameter  
Size  
Value  
4.46” x 3.23” x 2.14”  
7 oz.  
Comment  
Including Mounting Flanges  
Weight  
Mounting  
Deck or Bulkhead  
Environmental  
Parameter  
Value  
Exposed  
IP67  
IEC 60954 Classification  
Degree of Protection  
Operating Temperature  
Storage Temperature  
Relative Humidity  
Vibration  
-25°C to 55°C  
-40°C to 70°C  
93%RH @40° per IEC60945-8.2  
2-13.2Hz @ ±1mm, 13.2-100Hz @ 7m/s2 per IEC 60945-8.7  
12.5mm Nozzle @ 100liters/min from 3m for 30min per IEC 60945-8.8  
Ultraviolet B, A, Visible, and Infrared per IEC 60945-8.10  
Rain and Spray  
Solar Radiation  
Corrosion (Salt Mist)  
Electromagnet Emission  
Electromagnetic Immunity  
Safety Precautions  
4 times 7days @ 40°C, 95%RH after 2 hour Salt Spray Per IEC 60945-8.12  
Conducted and Radiated Emission per IEC 60945-9  
Conducted, Radiated, Supply, and ESD per IEC 60945-10  
Dangerous Voltage, Electromagnetic Radio Frequency per IEC 60945-12  
9 Technical Support  
If you require technical support for Maretron products, you can reach us in one of the following  
ways:  
Telephone: 1-866-550-9100  
Fax: 1-602-861-1777  
Mail: Maretron, LLC  
Attn: Technical Support  
9034 N. 23rd Ave Suite 13  
Phoenix, AZ 85021 USA  
Revision 1.8  
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SSC200 User’s Manual  
10Installation Template  
Please check the dimensions before using the following diagrams as templates for drilling the  
mounting holes because the printing process may have distorted the dimensions.  
3 87”  
1.42”  
Figure 10 – Horizontal Mounting Surface Template  
2.75”  
Figure 11 – Vertical Mounting Surface Template  
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Revision 1.8  
 
®
11 Maretron (2 Year) Limited Warranty  
Maretron warrants the SSC200 to be free from defects in materials and workmanship for two (2) years from the  
date of original purchase. If within the applicable period any such products shall be proved to Maretron’s  
satisfaction to fail to meet the above limited warranty, such products shall be repaired or replaced at Maretron’s  
option. Purchaser's exclusive remedy and Maretron’s sole obligation hereunder, provided product is returned  
pursuant to the return requirements below, shall be limited to the repair or replacement, at Maretron’s option, of  
any product not meeting the above limited warranty and which is returned to Maretron; or if Maretron is unable to  
deliver a replacement that is free from defects in materials or workmanship, Purchaser’s payment for such  
product will be refunded. Maretron assumes no liability whatsoever for expenses of removing any defective  
product or part or for installing the repaired product or part or a replacement therefore or for any loss or damage  
to equipment in connection with which Maretron’s products or parts shall be used. With respect to products not  
manufactured by Maretron, Maretron’s warranty obligation shall in all respects conform to and be limited to the  
warranty actually extended to Maretron by its supplier. The foregoing warranties shall not apply with respect to  
products subjected to negligence, misuse, misapplication, accident, damages by circumstances beyond  
Maretron’s control, to improper installation, operation, maintenance, or storage, or to other than normal use or  
service.  
THE FOREGOING WARRANTIES ARE EXPRESSLY IN LIEU OF AND EXCLUDES ALL OTHER EXPRESS OR  
IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF  
MERCHANTABILITY AND OF FITNESS FOR A PARTICULAR PURPOSE.  
Statements made by any person, including representatives of Maretron, which are inconsistent or in conflict with  
the terms of this Limited Warranty, shall not be binding upon Maretron unless reduced to writing and approved by  
an officer of Maretron.  
IN NO CASE WILL MARETRON BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, DAMAGES  
FOR LOSS OF USE, LOSS OF ANTICIPATED PROFITS OR SAVINGS, OR ANY OTHER LOSS INCURRED  
BECAUSE OF INTERRUPTION OF SERVICE. IN NO EVENT SHALL MARETRON’S AGGREGATE LIABILITY  
EXCEED THE PURCHASE PRICE OF THE PRODUCT(S) INVOLVED. MARETRON SHALL NOT BE SUBJECT  
TO ANY OTHER OBLIGATIONS OR LIABILITIES, WHETHER ARISING OUT OF BREACH OF CONTRACT OR  
WARRANTY, TORT (INCLUDING NEGLIGENCE), OR OTHER THEORIES OF LAW WITH RESPECT TO  
PRODUCTS SOLD OR SERVICES RENDERED BY MARETRON, OR ANY UNDERTAKINGS, ACTS OR  
OMISSIONS RELATING THERETO.  
Maretron does not warrant that the functions contained in any software programs or products will meet  
purchaser’s requirements or that the operation of the software programs or products will be uninterrupted or error  
free. Purchaser assumes responsibility for the selection of the software programs or products to achieve the  
intended results, and for the installation, use and results obtained from said programs or products. No  
specifications, samples, descriptions, or illustrations provided Maretron to Purchaser, whether directly, in trade  
literature, brochures or other documentation shall be construed as warranties of any kind, and any failure to conform  
with such specifications, samples, descriptions, or illustrations shall not constitute any breach of Maretron’s limited  
warranty.  
Warranty Return Procedure:  
To apply for warranty claims, contact Maretron or one of its dealers to describe the problem and determine the  
appropriate course of action. If a return is necessary, place the product in its original packaging together with  
proof of purchase and send to an Authorized Maretron Service Location. You are responsible for all shipping and  
insurance charges. Maretron will return the replaced or repaired product with all shipping and handling prepaid  
except for requests requiring expedited shipping (i.e. overnight shipments). Failure to follow this warranty return  
procedure could result in the product’s warranty becoming null and void.  
Maretron reserves the right to modify or replace, at its sole discretion, without prior notification, the warranty listed  
above. To obtain a copy of the then current warranty policy, please go to the following web page:  
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Appendix A – NMEA 0183 Interfacing  
SSC200 NMEA 0183 Transmitted Sentences  
HDG – Heading, Deviation & Variation  
The SSC200 indicates heading 10 times a second. The deviation field always contains zero as the  
SSC200 reports it’s heading with the deviation included. The variation field will normally contain the null  
character, however if the SSC200 receives either a valid RMC or VTG sentence, then the SSC200 will  
fill the variation field appropriately.  
$IIHDG,A,B,C,D,E*hh<CR><LF>  
Field A: Magnetic heading sensor including deviation in tenths of degrees  
B: Deviation always reads 0.0 because it is included in field A  
C: Although this field reads as “E”, it is meaningless as the deviation is always zero  
D: Null unless receiving variation data form RMC or VTG sentence in which case variation data  
E: Null unless receiving variation data from RMC or VTG sentence in which case E or W  
depending on direction of variation  
HDM – Heading, Magnetic  
The SSC200 does not normally transmit this sentence because it is no longer recommended for new  
designs by NMEA. However, this sentence can be enabled or turned on via a proprietary NMEA 0183  
sentence (see $PMARSETP definition).  
$IIHDM,A,B*hh<CR><LF>  
Field A: Magnetic heading sensor including deviation in tenths of degrees  
B: This field always contains an “M” indicating magnetic heading  
HDT – Heading, True  
The SSC200 does not normally transmit this sentence. However, this sentence can be enabled or  
turned on via a proprietary NMEA 0183 sentence (see $PMARSETP definition). The HDT sentence  
works in collaboration with the reception of an RMC or VTG sentence to produce true heading.  
$IIHDT,A,B*hh<CR><LF>  
Field A: Null unless receiving variation from RMC and VTG in which case magnetic heading including  
deviation and variation in tenths of degrees  
B: This field always contains a “T” indicating true magnetic heading  
ROT – Rate of Turn  
The SSC200 indicates the vessel’s rate of turn 5 times a second.  
$IIROT,A,B*hh<CR><LF>  
Field A: Rate of turn in degrees/minute where “-“ indicates the bow turning to port  
B: This field indicates whether data is valid, an “A” indicates that the data is valid where a “V”  
indicates invalid data  
MAROUT – Maretron Proprietary Output Sentence  
Since there is no standard NMEA 0183 sentence for indicating the vessel’s attitude (pitch and roll), the  
SSC200 uses a proprietary sentence to indicate pitch and roll one time per second.  
$PMAROUT,A,B,C,D,E,F,G,H,I*hh<CR><LF>  
Field A: Always reads “ATT” to indicate following data is associated with the vessel’s attitude  
B: Pitch angle in tenths of degrees, where “-“ indicates bow pitches downward  
C: Roll angle in tenths of degrees, where “-“ indicates roll to the port  
Revision 1.8  
Appendix A – NMEA 0183 Interfacing  
Page A1  
SSC200 User’s Manual  
D-I: Null  
TXT – Text Transmission  
The SSC200 transmits various status messages using the text transmission sentence.  
$IITXT,A,B,C,D*hh<CR><LF>  
Field A: Always reads “01”  
B: Always reads “01”  
C: Message identifier (see following table)  
D: Text string (see following table)  
Message  
Identifier  
Text String  
Description  
01  
Deviation Calibration  
Started  
This message is transmitted at the beginning of the magnetic deviation  
calibration process.  
02  
03  
Deviation Calibration  
Completed Successfully  
This message is transmitted upon successful completion of the magnetic  
deviation calibration process (i.e., a new deviation table has been stored  
in permanent memory).  
Deviation Calibration  
Failed to Complete  
The SSC200 attempts to perform calibration 5 times before giving up and  
issuing this sentence. Each time the SSC200 encounters an error (see  
message identifiers 04, 05, and 06) it restarts the calibration process.  
Upon the 5th error, the SSC200 exits the calibration routine and it must  
be restarted before it will once again try to perform deviation calibration.  
During calibration, the vessel must not turn to fast where the SSC200 is  
unable to reliably develop deviation data. If the SSC200 senses the  
vessel turning to quickly, it will issue this message and restart deviation  
calibration as long as it has not failed five times.  
During calibration, the vessel must not turn to slowly where the SSC200  
is unable to reliably develop deviation data. If the SSC200 senses the  
vessel turning to slowly, it will issue this message and restart deviation  
calibration as long as it has not failed five times.  
During calibration, the vessel must not jerk or reverse directions where  
the SSC200 is unable to reliably develop deviation data. If the SSC200  
senses an invalid movement, it will issue this message and restart  
deviation calibration as long as it has not failed five times.  
The SSC200 transmits this sentence once after it is powered up to  
indicate its serial number.  
The SSC200 transmits this sentence once after it is powered up to  
indicate its baud rate.  
The SSC200 transmits this sentence once after it is powered up to  
indicate its software version.  
The SSC200 transmits this sentence once after it is powered up to  
indicate its model version.  
The SSC200 transmits this sentence once after it is powered up to  
indicate its model identification.  
04  
05  
06  
Deviation Calibration  
Turning Too Fast  
Deviation Calibration  
Turning Too Slow  
Deviation Calibration  
Invalid Movement  
95  
96  
97  
98  
99  
Serial Number: xxxxxxx  
Baud Rate: 4800  
SW Version: 1.2  
Model Version: 1.0  
Model ID: SSC200  
Page A2  
Appendix A – NMEA 0183 Interfacing  
Revision 1.8  
®
SSC200 NMEA 0183 Received Sentences  
Note on NMEA 0183 Checksums  
For ease of manual configuration of the SSC200 via the NMEA 0183 Interface, NMEA 0183 checksums  
are optional. If no checksum is present in a received sentence, then the sentence is treated as if a valid  
checksum were present. If a checksum is present in a received sentence, then it is used to check the  
integrity of the sentence, which is accepted only if the calculated checksum agrees with the checksum  
at the end of the received sentence. To ensure the best possible data integrity, Maretron recommends  
using NMEA 0183 checksums whenever possible.  
RMC – Recommended Minimum Specific GNSS Data  
The SSC200 is capable of receiving the RMC sentence and extracting the magnetic variation data for  
subsequent insertion into the appropriate fields for transmission of the HDG and HDT sentences. The  
SSC200 uses an aging technique (referred to as “Variation Lifetime”) where variation data is output in  
the HDG and HDT sentences for a period of 5 seconds after the RMC sentence is received. The  
Variation Lifetime can be re-programmed to a shorter or longer period (see PMARSETP sentence).  
VTG – Course Over Ground and Ground Speed  
The SSC200 is capable of receiving the VTG sentence and computing the magnetic variation data for  
subsequent insertion into the appropriate fields for transmission of the HDG and HDT sentences. The  
variation is computed by observing the difference between the true course over ground and the  
magnetic course over ground. The SSC200 uses an aging technique (referred to as “Variation  
Lifetime”) where variation data is output in the HDG and HDT sentences for a period of 5 seconds after  
the VTG sentence is received. The Variation Lifetime can be re-programmed to a shorter or longer time  
period (see PMARSETP sentence).  
PMAREXE – Maretron Proprietary Execute Sentence  
The SSC200 can be commanded via this proprietary sentence to execute one of several commands.  
$PMAREXE,SSC200,,F0,,,,<CR><LF>  
This command causes the SSC200 to be reset and is useful for initiating deviation calibration.  
$PMAREXE,SSC200,,FD,0,,,<CR><LF>  
This command causes the SSC200 to stop outputting normal periodic data (like heading) and is useful  
for observing non-periodic sentences such as status sentences during deviation calibration.  
$PMAREXE,SSC200,,FD,1,,,<CR><LF>  
This command causes the SSC200 to once again output periodic data. Normally, periodic data is  
disabled during the calibration process such that status messages are easy to see and not lost within  
normal periodic data. This sentence is used to turn the periodic data back on.  
$PMAREXE,SSC200,,24,”known heading in tenths of degrees”,,,<CR><LF>  
This is the command used to perform installation-offset where the compass is aligned to a known  
heading and the pitch and roll are zeroed to the vesse’ls current attitude. If the current or known  
heading is 177.0°, then a value of 1770 should be programmed.  
$PMAREXE,SSC200,,5D,0,”variation”,,<CR><LF>  
This command causes the SSC200 to use a manual entry for variation (variation is programmed using  
1/10 of a degree resolution – as an example use 2.3 in the “variation” field for a 2.3° variation.  
$PMAREXE,SSC200,,5D,1,,,<CR><LF>  
This command causes the SSC200 to use variation data from the NMEA 2000® interface and ignore all  
other variation sources (i.e., NMEA 0183 interface and manual entries).  
Revision 1.8  
Appendix A – NMEA 0183 Interfacing  
Page A3  
SSC200 User’s Manual  
$PMAREXE,SSC200,,5D,2,,,<CR><LF>  
This command causes the SSC200 to use variation data from the NMEA 0183 interface and ignore all  
other variation sources (i.e., NMEA 2000® interface and manual entries).  
$PMAREXE,SSC200,,5D,3,,,<CR><LF>  
This command causes the SSC200 to be set back to the factory default where variation data is used  
from either the NMEA 0183 interface or the NMEA 2000® interface.  
$PMAREXE,SSC200,,5E,2,”damping period”,,<CR><LF>  
This command causes the SSC200 to use a rate of turn damping rate corresponding to the value  
programmed in “damping period”. The damping period is programmable from 100 to 60000, which  
represents 100ms to 60 seconds.  
$PMAREXE,SSC200,,5E,11,,,<CR><LF>  
This command causes the SSC200 to zero the rate of turn indication and record the compensation  
value used, along with the current operating temperature of the compass. The boat must remain at rest  
for a period of one minute after this command is issued.  
$PMAREXE,SSC200,,5E,12,,,<CR><LF>  
This command causes the SSC200 to cancel any rate of turn zeroing operations currently in progress.  
$PMAREXE,SSC200,,50,,,,<CR><LF>  
Will cause the SSC200 to retransmit the last deviation calibration status message  
PMARSETPX – Maretron Proprietary Set Period Sentence  
The SSC200 can be programmed to enable or disable the periodic transmission of the HDG, HDM,  
HDT, ROT, and PMAROUT sentences. In addition, the periodic transmission rate for these sentences  
and the Variation Lifetime (see RMC and VTG) can be programmed using this sentence.  
$PMARSETPX,SSC200,,A,B*hh<CR><LF>  
Field A: Identifier code, identifies the sentence or parameter to be programmed (see following table)  
B: Integer where “0” disables sentence and positive numbers are multipliers of 1ms (i.e.,  
programmed integer of 200 would mean a 200ms transmission interval)  
Identifier Code  
Sentence  
HDG  
Default Rate  
100 (100ms)  
0 or Disabled  
0 or Disabled  
200 or 200ms  
1000 or 1sec  
5000 or 5sec  
00  
01  
02  
03  
04  
0A  
HDM  
HDT  
ROT  
PMAROUT  
Variation Lifetime  
Some example sentences are shown below:  
1. To disable transmission of the HDG sentence:  
$PMARSETPX,SSC200,,00,0  
2. To enable transmission of the HDG sentence at intervals of 100 ms:  
$PMARSETPX,SSC200,,00,100  
3. To disable transmission of the HDM sentence:  
$PMARSETPX,SSC200,,01,0  
4. To enable transmission of the HDM sentence at intervals of 1000 ms:  
$PMARSETPX,SSC200,,01,1000  
Page A4  
Appendix A – NMEA 0183 Interfacing  
Revision 1.8  
®
5. To disable transmission of the HDT sentence:  
$PMARSETPX,SSC200,,02,0  
6. To enable transmission of the HDT sentence at intervals of 100 ms:  
$PMARSETPX,SSC200,,02,100  
7. To disable transmission of the ROT sentence:  
$PMARSETPX,SSC200,,03,0  
8. To enable transmission of the ROT sentence at intervals of 100 ms:  
$PMARSETPX,SSC200,,03,100  
9. To disable transmission of the PMAROUT sentence:  
$PMARSETPX,SSC200,,04,0  
10.To enable transmission of the PMAROUT sentence at intervals of 1 sec:  
$PMARSETPX,SSC200,,04,1000  
PMARSETP – Maretron Proprietary Set Period Sentence  
NOTE: This sentence is included for compatibility with older versions of SSC200 firmware. The  
PMARSETPX sentence offers finer resolution and should be used if available.  
The SSC200 can be programmed to enable or disable the periodic transmission of the HDG, HDM,  
HDT, ROT, and PMAROUT sentences. In addition, the periodic transmission rate for these sentences  
and the Variation Lifetime (see RMC and VTG) can be programmed using this sentence.  
$PMARSETP,SSC200,,A,B*hh<CR><LF>  
Field A: Identifier code, identifies the sentence or parameter to be programmed (see following table)  
B: Integer where “0” disables sentence and positive numbers are multipliers of 1ms (i.e.,  
programmed integer of 2 would mean a 200ms transmission interval)  
Identifier Code  
Sentence  
HDG  
Default Rate  
1 or 100ms  
0 or Disabled  
0 or Disabled  
2 or 200ms  
10 or 1sec  
00  
01  
02  
03  
04  
0A  
HDM  
HDT  
ROT  
PMAROUT  
Variation Lifetime  
50 or 5sec  
SSC200 NMEA 0183 Initiated Deviation Calibration  
NMEA 0183 initiated deviation calibration is accomplished by turning the vessel through at  
least 3 complete circles after the SSC200 receives a Maretron proprietary NMEA 0183  
sentence. The procedure is as follows:  
1. Ensure that the compass has been properly installed per Section 2,  
2. Warm up the compass by operating it for approximately 10 minutes,  
3. Turn the vessel (either direction) such that you complete a full 360° turn in 2½ minutes  
or less (try not to go below 1 minute for a complete circle),  
4. Send the following Maretron proprietary NMEA0183 sentence to the SSC200 while  
continuing to turn the vessel:  
a. $PMAREXE,SSC200,,FD,0,,,<CR><LF> This will turn off all periodic transmissions  
such that you can easily see status messages associated with the calibration  
process  
b. $PMAREXE,SSC200,,F0,,,,<CR><LF> This will initiate a reset and force the  
SSC200 to start the calibration process  
Revision 1.8  
Appendix A – NMEA 0183 Interfacing  
Page A5  
SSC200 User’s Manual  
5. Continue turning the vessel through at least 3 circles until you see one of the following  
Maretron proprietary sentences:  
a. $IITXT,01,01,02,Deviation Calibration Successfully Completed*17<CR><LF> This  
sentence indicates a successful calibration and you can jump to step number 6.  
b. $IITXT,01,01,03,Deviation Calibration Failed To Complete*43<CR><LF> This  
sentence indicates that the calibration failed (return to step number 1).  
6. Turn the periodic transmissions back on by sending the following Maretron proprietary  
NMEA0183 sentence to the SSC200 - $PMAREXE,SSC200,,FD,1,,,<CR><LF>  
7. Proceed to Installation-Offset Correction  
SSC200 NMEA 0183 Installation-Offset Correction  
Installation-offset correction can be performed by sending a Maretron proprietary NMEA 0183  
sentence to the SSC200. The procedure is as follows:  
1. Make sure the vessel is laying in flat water on a known heading,  
2. Send the following Maretron proprietary NMEA 0183 sentence to the SSC200:  
$PMAREXE,SSC200,,24,”known heading in tenths of degrees”,,,<CR><LF>  
Where “known heading in tenths of degrees” is expressed in 10th of degrees (i.e., 121.7°  
would be programmed as 1217)  
Sending this Maretron proprietary NMEA 0183 sentence to the SSC200 causes the heading,  
roll, and pitch offsets to be written to permanent memory.  
Page A6  
Appendix A – NMEA 0183 Interfacing  
Revision 1.8  
®
Appendix B – NMEA 2000® Interfacing  
SSC200 NMEA 2000® Periodic Data Transmitted PGNs  
PGN 127250 – Vessel Heading  
The SSC200 uses this PGN to indicate the vessel’s heading. The Heading Sensor Reading  
(field 2) includes deviation, therefore Deviation (field 2) always contains zero. Variation (field 4)  
is not provided by the SSC200, therefore this field always contains a value of 0x7FFF (data not  
available). Since the SSC200’s core technology is based on magnetometers, the Heading  
Sensor Reference (field 5) is always set to magnetic.  
Field 1: SID – The sequence identifier field is used to tie related PGNs together. For example,  
the SSC200 will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude  
(127257), and Rate of Turn (127251) to indicate that the readings are linked together  
(i.e., the data from each PGN was taken at the same time although they are reported  
at slightly different times).  
2: Heading Sensor Reading – This field is used to report the vessel’s heading and  
includes deviation assuming a deviation table has been successfully loaded through  
the magnetic deviation calibration process.  
3: Deviation – The deviation is included in field 2, therefore this field always reads as 0.  
4: Variation – The SSC200 does not use this field so the field is transmitted with the  
value 0x7FFF (data not available). See PGN 127258 for information regarding the  
SSC200 and its ability to transmit magnetic variation.  
5: Heading Sensor Reference – The SSC200 transmits a “1” in this field to indicate that  
the heading is referenced to magnetic North  
6: Reserved – This field is reserved by NMEA; therefore, the SSC200 sets all bits to a  
logic 1.  
PGN 127251 – Rate of Turn  
The SSC200 uses this PGN to indicate the vessel’s rate of turn.  
Field 1: SID – The sequence identifier field is used to tie related PGNs together. For example,  
the SSC200 will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude  
(127257), and Rate of Turn (127251) to indicate that the readings are linked together  
(i.e., the data from each PGN was taken at the same time although they are reported  
at slightly different times).  
2: Rate of Turn – This field is used to report the vessel’s rate of turn.  
3: Reserved – This field is reserved by NMEA; therefore, the SSC200 sets all bits to a  
logic 1.  
PGN 127257 – Attitude  
The SSC200 uses this PGN to indicate the vessel’s attitude (pitch and roll). The Yaw (field 2)  
is not used, therefore this field always contains 0x7FFF (data not available).  
Field 1: SID – The sequence identifier field is used to tie related PGNs together. For example,  
the SSC200 will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude  
(127257), and Rate of Turn (127251) to indicate that the readings are linked together  
(i.e., the data from each PGN was taken at the same time although they are reported  
at slightly different times).  
Revision 1.8  
Appendix B – NMEA 2000® Interfacing  
Page B1  
SSC200 User’s Manual  
2: Yaw – This field always contains a value of 0x7FFF (data not available).  
3: Pitch – This field is used to report the vessel’s pitch.  
4: Roll – This field is used to report the vessel’s roll.  
5: Reserved – This field is reserved by NMEA; therefore, the SSC200 sets all bits to a  
logic 1.  
PGN 127258 – Magnetic Variation  
The SSC200 may or may not periodically transmit this PGN depending on whether or not it has  
been programmed with the local magnetic variation. Programming the magnetic variation  
(through a Maretron display product like the DSM200) will cause the SSC200 to transmit this  
PGN once per second. If the local magnetic variation is not known, then the variation can be  
disabled (again, through a display product like the DSM200) at which time the SSC200 will  
cease to transmit this PGN.  
Field 1: SID – The sequence identifier field is used to tie related PGNs together. For example,  
the SSC200 will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude  
(127257), and Rate of Turn (127251) to indicate that the readings are linked together  
(i.e., the data from each PGN was taken at the same time although they are reported  
at slightly different times).  
2: Variation Source – This field always contains a value of 0x00 (manual entry).  
3: Reserved – This field is reserved by NMEA; therefore, the SSC200 sets all bits to a  
logic 1.  
4: Age of Service – This field always contains a value of 0x7FFF (data not available).  
5: Variation – This field is used to report the local magnetic variation as entered by the  
user. Positive values are Easterly and negative values are Westerly.  
WARNING: Magnetic variation changes as your location on the earth changes and it  
should be adjusted with these changes. Neither the DSM200 nor the SSC200 will make  
these changes automatically; they are the responsibility of the user.  
SSC200 NMEA 2000® Non-Periodic Data Transmitted PGNs  
PGN 126270 – Maretron Proprietary Slave Response – Deviation Calibration Status  
This indicates the status of the deviation calibration process.  
Field 1: Maretron Vendor ID and Industry Code (16 bits) – this field’s value will be 0x9889  
2: Product Code (16 bits) – this field’s value will be 0x1B2, which is the NMEA 2000®  
product code for the SSC200.  
3: Software Code (16 bits) – this field’s value will be 0x0001, which is the identifier for  
this version of the Maretron proprietary protocol  
4: Command (8 bits) – this field’s value will be 0x50, which indicates that this response  
contains status for deviation calibration  
5: Status Code (8 bits) – this field will indicate the status of the calibration process with  
one of the values from the following table (see following table).  
Page B2  
Appendix B – NMEA 2000® Interfacing  
Revision 1.8  
®
Status  
Code  
01  
Message Name  
Description  
Deviation Calibration  
Started  
This message is transmitted at the beginning of the magnetic  
deviation calibration process.  
02  
03  
Deviation Calibration  
This message is transmitted upon successful completion of the  
Completed Successfully magnetic deviation calibration process (i.e., a new deviation table  
has been stored in permanent memory).  
Deviation Calibration  
Failed to Complete  
The SSC200 attempts to perform calibration 5 times before  
giving up and issuing this sentence. Each time the SSC200  
encounters an error (see message identifiers 04, 05, and 06) it  
restarts the calibration process. Upon the 5th error, the SSC200  
exits the calibration routine and it must be restarted before it will  
once again try to perform deviation calibration.  
04  
05  
06  
Deviation Calibration  
Turning Too Fast  
During calibration, the vessel must not turn to fast where the  
SSC200 is unable to reliably develop deviation data. If the  
SSC200 senses the vessel turning to quickly, it will issue this  
message and restart deviation calibration as long as it has not  
failed five times.  
During calibration, the vessel must not turn to slowly where the  
SSC200 is unable to reliably develop deviation data. If the  
SSC200 senses the vessel turning to slowly, it will issue this  
message and restart deviation calibration as long as it has not  
failed five times.  
During calibration, the vessel must not jerk or reverse directions  
where the SSC200 is unable to reliably develop deviation data. If  
the SSC200 senses an invalid movement, it will issue this  
message and restart deviation calibration as long as it has not  
failed five times.  
Deviation Calibration  
Turning Too Slow  
Deviation Calibration  
Invalid Movement  
SSC200 NMEA 2000® Received PGNs  
PGN 126208 – NMEA Command Group Function – Maretron Proprietary Reset  
This will initiate a reset and force the SSC200 to start the calibration process.  
Field 1: Complex Command Group Function Code (8 bits) – set this field’s value to 0x01,  
which denotes a command PGN  
2: Commanded PGN (24 bits) – set this field’s value to 126720, which denotes the  
Maretron proprietary PGN  
3: Priority Setting (4 bits) – set this field’s value to 0x8, which indicates to leave priority  
settings unchanged  
4: Reserved (4 bits) – set this field’s value to 0xF, which is the value for a reserved field  
of this size  
5: Number of Pairs of Commanded Parameters to Follow (8 bits) – set this field’s value  
to 0x4, indicating that four parameters will follow  
6: Number of First Commanded Parameter (8 bits) – set this field’s value to 0x1  
7: Maretron Vendor ID and Industry Code (16 bits) – set this field’s value to 0x9889  
8: Number of Second Commanded Parameter (8 bits) – set this field’s value to 0x02  
9: Product Code (16 bits) – set this field’s value to 0x1B2, which is the NMEA 2000®  
product code for the SSC200.  
10: Number of Third Commanded Parameter (8 bits) – set this field’s value to 0x03  
11: Software Code (16 bits) – set this field’s value to 0x0001, which is the identifier for  
this version of the Maretron proprietary protocol  
Revision 1.8  
Appendix B – NMEA 2000® Interfacing  
Page B3  
SSC200 User’s Manual  
12: Maretron Command – set this field’s value to 0xF0, which will initiate a reset and start  
the calibration process.  
PGN 126208 – NMEA Command Group Function – Maretron Proprietary Installation  
Offset. This PGN performs the installation offset of the compass. It sets the roll and pitch  
outputs to zero at the compass’ current orientation and sets the heading reading for the current  
orientation to the value given by the PGN (see page B3 for complete description of PGN  
126270).  
Field 1: Complex Command Group Function Code (8 bits) – set this field’s value to 0x01,  
which denotes a command PGN  
2: Commanded PGN (24 bits) – set this field’s value to 126720 decimal (0x1EF00  
hexadecimal), which denotes the Maretron proprietary PGN  
3: Priority Setting (4 bits) – set this field’s value to 0x8, which indicates to leave priority  
settings unchanged  
4: Reserved (4 bits) – set this field’s value to 0xF, which is the value for a reserved field  
of this size  
5: Number of Pairs of Commanded Parameters to Follow (8 bits) – set this field’s value  
to 0x4, indicating that four parameters will follow  
6: Number of First Commanded Parameter (8 bits) – set this field’s value to 0x1  
7: Maretron Vendor ID and Industry Code (16 bits) – set this field to 0x9889, which is a  
combination of Maretron’s vendor ID and the marine industry code  
8: Number of Second Commanded Parameter (8 bits) – set this field’s value to 0x02  
9: Product Code (16 bits) – set this field’s value to 0x1B2, which is the NMEA 2000®  
product code for the SSC200.  
10: Number of Third Commanded Parameter (8 bits) – set this field’s value to 0x03  
11: Software Code (16 bits) – set this field’s value to 0x0001, which is the identifier for  
this version of the Maretron proprietary protocol  
12: Maretron Command (8 bits) – set this field’s value to 0x24, which will cause  
installation-offset calibration to be performed  
13: Heading Value (16 bits) – set this field’s value to the current known heading in tenths  
of degrees (a value between 0 and 3599). For example, 121.7° would be  
programmed as 1217 decimal, or 0x4C1 hexadecimal.  
PGN 126208 – NMEA Request Group Function – Transmission Periodic Rate  
This PGN will enable or disable the periodic transmission of specific PGNs.  
Field 1: Complex Command Group Function Code (8 bits) – set this field’s value to 0x00,  
which denotes a request PGN  
2: Requested PGN (24 bits) – set this field’s value to the corresponding PGN for which  
you wish to change the periodic rate.  
3: Transmission Interval (32 bits) – set this field’s value to 0x0 to disable the periodic  
transmission of the PGN identified in field 2 above. Otherwise, program in the default  
periodic rate to restore periodic transmission of the PGN identified in field 2 above.  
The resolution of this field is 1 millisecond.  
4: Transmission Interval Offset (16 bits) – set this field’s value to 0xFFFF; all other  
values will cause the request to be rejected.  
5: Number of Pairs of Commanded Parameters to Follow (8 bits) – set this field’s value  
to 0x0.  
Page B4  
Appendix B – NMEA 2000® Interfacing  
Revision 1.8  
®
SSC200 NMEA 2000® Initiated Deviation Calibration  
NMEA 2000® initiated deviation calibration is accomplished by turning the vessel through at  
least 3 complete circles after the SSC200 receives a Maretron proprietary NMEA 2000® PGN.  
The procedure is as follows:  
1. Ensure that the compass has been properly installed per Section 2,  
2. Warm up the compass by operating it for approximately 10 minutes,  
3. Turn the vessel (either direction) such that you complete a full 360° turn in 2½ minutes  
or less (try not to go below 1 minute for a complete circle),  
4. Send the following NMEA 2000® PGN to the SSC200 while continuing to turn the  
vessel:  
PGN 126208 – NMEA Command Group Function – Maretron Proprietary Reset.  
This will initiate a reset and force the SSC200 to start the calibration process (see page  
B3 for complete description of PGN 126208).  
5. Continue turning the vessel through at least 3 circles until you see one of the following  
Maretron proprietary NMEA 2000® PGNs:  
a. PGN 126270 – Maretron Proprietary Slave Response – Deviation Calibration  
Successfully Completed. This indicates successful completion of the deviation  
calibration process (see page B2 for complete description of PGN 126270).  
b. PGN 126270 – Maretron Proprietary Slave Response – Deviation Calibration  
Failed to Complete. This indicates a failure of the deviation calibration process  
(see page B2 for complete description of PGN 126270).  
SSC200 NMEA 2000® Installation-Offset Correction  
Installation-offset correction can be performed by sending a Maretron proprietary NMEA 2000®  
PGN to the SSC200. The procedure is as follows:  
1. Make sure the vessel is laying in flat water on a known heading,  
2. Send the following NMEA 2000® PGN to the SSC200:  
a. PGN 126208 – NMEA Command Group Function – Maretron Proprietary  
Installation Offset. This PGN performs the installation offset of the compass. It  
sets the roll and pitch outputs to zero at the compass’ current orientation and  
sets the heading reading for the current orientation to the value given by the PGN  
(see page B2 for a complete description of PGN 126270).  
Revision 1.8  
Appendix B – NMEA 2000® Interfacing  
Page B5  
SSC200 User’s Manual  
This page intentionally left blank  
Page B6  
Appendix B – NMEA 2000® Interfacing  
Revision 1.8  
®
Appendix C – Connecting to a PC Via NMEA 0183  
In order to perform configuration of the SSC200 over the NMEA 0183 interface, it is preferable that the  
connection be made by a RS-232 to RS-422 level converter. In the case that a level converter is not available,  
the following method can be attempted:  
1. Connect the SSC200 to the PC's serial port. Please note that the SSC200 uses RS-422 signal levels,  
while PC serial ports operate with RS-232 signal levels. If you do not have a RS-232 to RS-422 level  
converter, some people have reported success connecting directly to a RS-232 serial port using the  
following connections:  
a. Connect TXB (brown) and RXB (white) together and to the System Ground pin (GND, pin 5) of  
the RS-232 port.  
b. Connect TXA (gray) to the Receive Data pin (RXD, pin 2) of the RS-232 port.  
c. Connect RXA (blue) to the Transmit Data pin (TXD, pin 3) of the RS-232 port.  
Ensure that the NMEA 0183 signals from the SSC200 are connected to nothing else besides the  
computer’s RS-232 port to avoid ground loops. While some people have had success with this method,  
Maretron cannot guarantee that such a connection will work with every computer and highly recommends  
the use of a level converter.  
2. Connect power to the compass:  
a. Connect 9-16 VDC to V+ (red).  
b. Connect system ground to V- (black).  
3. Start Hyperterm and connect it to the port to which the SSC200 is connected (4800 or 38400 bps,  
depending on the baudrate the compass is set to, 8 data bits, no parity, 1 stop bit). You should now see  
compass data in the form of NMEA0183 sentences on the Hyperterm screen.  
4. Type "shell".  
The NMEA0183 sentences will stop and a "cmd>" prompt will appear.  
Revision 1.8 Appendix C – Connecting to a PC Via NMEA 0183  
Page C1  
SSC200 User’s Manual  
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Page C2  
Appendix C – Connecting to a PC Via NMEA 0183 Revision 1.8  
®
Appendix D – Configuring the SSC200 to Transmit True  
Heading Data  
The SSC200 is factory configured to transmit magnetic heading data on the NMEA0183 interface. Some NMEA  
0183 applications require true heading data. This application note describes how to configure the SSC200 to  
transmit true heading data  
Prerequisites:  
The SSC200 compass must have firmware revision 1.7 or greater.  
The SSC200 compass must either transmit the default HDG sentence or be configured to transmit the  
HDT sentence (see Application Note #1, “Configuring the SSC200 to Transmit the HDT Sentence for  
Satellite Antennas and Radars”).  
Instructions:  
There are two choices for a magnetic variation source for the SSC200, GPS (preferred) or manual.  
GPS Variation  
In order to use a GPS to enable the SSC200 compass to transmit true heading data, the GPS antenna must  
transmit magnetic variation data. Not all GPS antennas transmit magnetic variation data. Please consult the GPS  
antenna user’s manual for details.  
1. Ensure that the GPS antenna is configured to transmit either the RMC or VTG sentence. Either sentence  
should work equally well.  
2. Connect the NMEA 0183 output of the GPS antenna to the NMEA 0183 input of the SSC200. Please note  
the following cable connections on the SSC200:  
GPS Connection  
TXA (TX+)  
TXB (TX-)  
SSC200 Connection  
Blue Wire, RXA (RX+)  
White wire, RXB (RX-)  
3. The SSC200 should now be transmitting true heading data. Examine the NMEA 0183 sentences coming  
from the SSC200 or check the heading indication on the system connected to the NMEA 0183 output of  
the SSC200 for true heading data.  
4. If no true heading data is observed at this point, try  
d. switching the wires on the GPS->SSC200 connection, as not all manufacturers are consistent in  
their labeling of the NMEA 0183 wires  
e. ensuring the SSC200 is configured to transmit either HDG or HDT  
f. ensuring the GPS antenna is transmitting Magnetic Variation Data. The sentences should look  
one of the sentences below, where the lowercase letter placeholders are replaced with numerical  
values.  
$GPRMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxxxx,x.x,a,a*hh  
The two underlined fields contain the magnetic variation data and must be present in order  
for this sentence to be used for magnetic variation.  
$GPVTG,x.x,T,x.x,M,x.x,N,x.x,K,a*hh  
The two underlined fields contain the true and magnetic course over ground data. Both  
values must be present in order for this sentence to be used for magnetic variation.  
Manual Variation  
1. Connect the SSC200 to the PC's serial port and obtain the “cmd>” prompt per the instructions in  
Appendix C.  
2. To program the SSC200 with a manually magnetic variation value, type the following sentence  
Revision 1.8  
Appendix D – Transmitting True Heading Data  
Page D1  
SSC200 User’s Manual  
$PMAREXE,SSC200,,5D,0,<variation>,,  
Where <variation> is the magnetic variation in units of degrees and resolution in tenth of degrees –  
positive values represent easterly variation, and negative values represent westerly variation.  
For example, to program the SSC200 with 18.0° easterly magnetic variation, as might be seen in Seattle,  
WA, USA, type the sentence:  
$PMAREXE,SSC200,,5D,0,18.0,,  
To program the SSC200 with 5.5° westerly magnetic variation, as might be seen on the east coast of  
Florida, USA, type the sentence:  
$PMAREXE,SSC200,,5D,0,-5.5,,  
5. The SSC200 should now be transmitting true heading data. Examine the NMEA 0183 sentences coming  
from the SSC200 or check the heading indication on the system connected to the NMEA 0183 output of  
the SSC200 for true heading data.  
Page D2  
Appendix D – Transmitting True Heading Data  
Revision 1.8  
®
Appendix E - Configuring the SSC200 to Transmit the HDT  
Sentence for Satellite Antennas and Radars  
The SSC200 is factory configured to transmit the HDG sentence 10 times per second. However, certain satellite  
antennas and radars need the HDT sentence. This application note explains how to change the transmitted  
sentence from to HDT.  
Prerequisites:  
The SSC200 compass must have firmware revision 1.7 or greater.  
The SSC200 compass must have a GPS source for magnetic variation information or must be manually  
programmed with the local magnetic variation (Please see Maretron Application Note #2, “Configuring the  
SSC200 to transmit True Heading Data”)  
Instructions:  
1. Connect the SSC200 to the PC's serial port and obtain the “cmd>” prompt per the instructions in  
Appendix C.  
2. To disable transmission of the HDG sentence, type the following sentence:  
$PMARSETPX,SSC200,,00,0  
3. To enable transmission of the HDT sentence at 100 ms intervals (10 times per second), type the  
sentence:  
$PMARSETPX,SSC200,,02,100  
*Note: For compasses with firmware revision 1.8 or greater, a NMEA 0183 checksum is optional. For  
compasses with earlier firmware revisions, a correct NMEA 0183 checksum is required.  
4. Type “exit” or simply power the SSC200 off and then on again. You should now observe HDT sentences  
being transmitted.  
Revision 1.8  
Appendix E – Transmitting the HDT Sentence  
Page E1  
SSC200 User’s Manual  
This page intentionally left blank  
Page E2  
Appendix E – Transmitting the HDT Sentence  
Revision 1.8  
®
Appendix F – Changing the NMEA0183 Identifier  
Transmitted by the SSC200  
The identifier for NMEA0183 sentences transmitted by the SSC200 is set by the factory to be “II”; however, some  
users may need to change this to other values. This addendum explains how to change the NMEA 0183 identifier  
for the SSC200.  
Prerequisites:  
The SSC200 compass must have firmware revision 1.7 or greater.  
Instructions:  
1. Connect the SSC200 to the PC's serial port and obtain the “cmd>” prompt per the instructions in  
Appendix C.  
2. Type the following sentence  
$PMAREXE,SSC200,,DF,??,,,  
Where ?? is replaced by the two-character identifier you wish the SSC200 to transmit (for example, to  
change to a heading of HE, type the sentence  
$PMAREXE,SSC200,,DF,HE,,,  
*Note: For compasses with firmware revision 1.8 or greater, a NMEA 0183 checksum is optional. For  
compasses with earlier firmware revisions, a correct NMEA 0183 checksum is required.  
3. Type “exit” or simply power the SSC200 off and then on again. You should now observe sentences being  
transmitted using the desired NMEA 0183 identifier.  
Revision 1.8  
Appendix F – Changing the NMEA 0183 Identifier  
Page F1  

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